Torrential rainfall Thursday into Friday first drove small streams out of their banks and will lead to flooding of the Potomac River and others in the mid-Atlantic this weekend.
Multiple roads were closed from North Carolina to upstate New York early Friday as a round of heavy rain moved into the area and stalled.
From 2 to 6 inches of rain fell on part of the Potomac River basin this week and has been enough to cause the waterway to rise.
Moderate to major flooding is forecast by National Weather Service hydrologists from Harper's Ferry, West Virginia, to Washington, D.C.
With the river level forecast, unprotected areas of the waterfront at the Washington, D.C., seafood market would be flooded. In the Georgetown section of the District of Columbia, the volume of water moving downstream will supersede tide levels.
Farther south, heavy rain fell across portions of southern Virginia and the Carolinas Wednesday night through Thursday, and streams and rivers swelled out of their banks.
Moderate flooding is forecast along portions of the Roanoke River in Virginia. The Neuse River at Smithfield and Goldsboro, North Carolina, is forecast to reach moderate flood stage or higher this weekend. The Tar River at Rocky Mount, North Carolina, is also projected to reach moderate flood stage.
People in unprotected areas along the river will need to relocate. Park land and roadways along the river will take on water, and people should avoid these areas until waters recede early next week.
Farther north, less intense, less widespread heavy rain has fallen over much of the Susquehanna River Basin. While a significant rise is forecast along much of both branches of the river this weekend, in most cases waters will stop short of moderate flood levels.
The duration and intensity of the rain is forecast is not expected to cause major river flooding in New England this weekend.
Only spotty shower activity is forecast this weekend into early next week in the wake of the heavy rainfall.
Small streams will recede and runoff from streams feeding into the major rivers will diminish allowing the large waterways to crest.